Technical Documentation

┌─────────────────────────────────────────────────────┐
│  Chrome Extension (Manifest V3)                     │
│                                                     │
│  ┌──────────────┐     ┌───────────────────────────┐ │
│  │   Popup UI   │     │     Content Script         │ │
│  │  (React)     │     │   (meet.google.com)        │ │
│  │              │     │                            │ │
│  │  - Toggle    │     │  ┌────────────────────┐   │ │
│  │  - Meter     │◄───►│  │  Audio Analyser    │   │ │
│  │  - Settings  │     │  │  (Web Audio API)   │   │ │
│  │              │     │  └────────┬───────────┘   │ │
│  └──────────────┘     │           │               │ │
│         ▲             │  ┌────────▼───────────┐   │ │
│         │             │  │  State Machine     │   │ │
│         │             │  │  IDLE → MUTED →    │   │ │
│         │             │  │  SPEAKING → GRACE  │   │ │
│         │             │  └────────┬───────────┘   │ │
│         │             │           │               │ │
│         │             │  ┌────────▼───────────┐   │ │
│         │             │  │  Mute Controller   │   │ │
│         │             │  │  (DOM manipulation)│   │ │
│         │             │  └────────────────────┘   │ │
│         │             └───────────────────────────┘ │
│         │                                           │
│         └─── Chrome Storage API (config/state sync)─┘
│                                                     │
└─────────────────────────────────────────────────────┘

src/
├── constants.ts          # Constants, modes, thresholds, storage keys
├── messages.ts           # i18n messages (EN/JA)
├── i18n.ts               # Locale management
├── manifest.ts           # Chrome extension manifest definition
├── background/
│   └── service-worker.ts # Service Worker (game launcher, etc.)
├── content/
│   └── index.ts          # Content Script (state machine, mode control, shortcuts)
└── popup/
    ├── index.html        # Popup entry HTML
    ├── main.tsx          # React mount
    ├── Popup.tsx         # Popup UI component
    ├── popup.css         # Styles
    ├── Equalizer.tsx     # Spectrum analyser
    ├── ThemeSwitcher.tsx # Theme switcher
    ├── LocaleSwitcher.tsx# Language switcher
    └── GameLauncher.tsx  # Mini-game launcher

Uses the Web Audio API AnalyserNode to measure microphone input volume in real time.

getUserMedia() → AudioContext → MediaStreamSource → AnalyserNode
                                                          │
                                                    getFloatTimeDomainData()
                                                          │
                                                    RMS (Root Mean Square) calculation

Configuration parameters:

A finite state machine with 5 states manages the speech state.

IDLE ──(mode other than Off selected)──► MUTED ──(volume > speechThreshold)──► UNMUTING ──► SPEAKING
                     ▲                                                │
                     │                              (volume < silenceThreshold)
                     │                                                │
                     └──(graceTimer expired)── GRACE ◄────────────────┘
                                                │
                                         (volume > silenceThreshold)
                                                │
                                                ▼
                                            SPEAKING

* If the user manually toggles the Meet microphone, the mode stays the same and only the state follows.

Four modes control how state transitions behave. Off is the control-disabled mode.

Provides a customizable keyboard shortcut (default: Ctrl+Shift+M).

• Off: Disabled
• Auto: Toggle mute
• Auto-Off: Toggle mute
• Push-to-Talk: Unmute only while key is held (hold operation)

The shortcut key can be freely changed from the popup settings.

Different thresholds for unmuting and muting prevent chattering (frequent toggling).

speechThreshold (speech start)  = 0.025  (default)
silenceThreshold (silence)      = speechThreshold × 0.5 = 0.0125

  Volume
   ▲
   │  ┄┄┄┄┄┄┄┄┄ speechThreshold (0.025) ┄┄┄┄  ← Unmute when exceeded
   │
   │  ┄┄┄┄┄┄┄┄┄ silenceThreshold (0.0125) ┄┄  ← Grace period starts when below
   │
   └──────────────────────────────────────────► Time

Detects the Google Meet mute button using multiple strategies:

1. Search by aria-label attribute (supports Japanese/English)
2. Search by data-tooltip attribute
3. Fallback: simulate Ctrl+D keyboard shortcut

Mute state is determined from the data-is-muted attribute or the aria-label text content.

A settings UI built with React 19. Synchronizes state with the Content Script in real time via the Chrome Storage API.

• Mode selector: Switch between Off / Auto / Auto-Off / Push-to-Talk
• Status display: Shows the current state (muted/speaking/grace) with a dot indicator
• Level meter: Displays microphone input level in real time (with threshold markers)
• Sensitivity slider: Adjust speechThreshold (0.005–0.25) — saved per mode
• Grace period slider: Adjust gracePeriod (500ms–4000ms) — saved per mode
• Shortcut key settings: Customization via key recording UI
• Microphone device selection: Manual selection of the microphone to use

Popup → Chrome Storage → Content Script
  │                            │
  │  hushMeetConfig: object    │  (sensitivity/grace period settings)
  │  hushMeetMode: string      │  (operating mode)
  │  hushMeetShortcutKey: str  │  (shortcut key)
  │                            │
  │                            ▼
  │                      Content Script → Chrome Storage → Popup
  │                            │
  │                            │  hushMeetState: string  (current state)
  │                            │  hushMeetLevel: number  (volume level)
  │                            │  hushMeetSpectrum: array (spectrum)
  └────────────────────────────┘

The Popup and Content Script do not communicate directly; they communicate bidirectionally via Chrome Storage API change events.

Commands

• Voice detection is RMS (volume) based, so it may false-trigger on loud ambient noise (mitigated by using Auto-Off mode)
• Google Meet UI changes may break mute button detection
• The very beginning of speech may be cut off (adjustable via threshold settings)
• The shortcut key only works when the Google Meet tab is focused

• Voice-weighted noise gate for improved detection accuracy
• Pre-speech buffering to reduce beginning-of-utterance clipping
• Auto-detection logic to follow Google Meet UI changes
• Silero VAD (ML-based) replacement for higher detection accuracy